Battery-powered IP/surveillance cameras have a very limited power budget and, therefore, cannot record all the time. To preserve power, battery-powered IP/surveillance cameras have a particular off/on duty cycle that allows the camera to record only when something interesting is happening in the field of view of the camera.
Currently available cameras control a duty cycle using a mounted passive infrared (PIR) sensor with a small microcontroller unit (MCU) attached. The camera sensor and processor remain off and only the PIR and MCU are on in the normal case. When the PIR is triggered by motion, the MCU wakes up the camera processor, which initializes the camera sensor and starts recording.
One problem is that PIR is triggered too often. Sometimes PIR is triggered by trivial events like changes in lighting, wind, or moving tree branches (false motion).
Initializing the camera due to a false motion unnecessarily drains power and wastes resources. Additional strategies involve the use of multiple PIR sensors with varying sensitivities and ranges, the use of a CO2 sensor, and the use of a contact microphone to determine when the camera should exit standby mode and start recording. Each type of sensor has flaws that can result in false positive detections.
It would be desirable to implement a multi-stage wakeup battery-powered IP camera to provide a better hypothesis testing (screening) mechanism in order to minimize the amount of electric power wasted on such false positives.